shill: Fix disconnect metrics values.
Change Disconnect histogram min=1, max=2, num_buckets=3.
BUG=chromium-os:33248
TEST=Unit tests, Manually verify using about:histograms.
Change-Id: If4250dec633b6ad7a72b65b5c120106534119672
Reviewed-on: https://gerrit.chromium.org/gerrit/29203
Tested-by: Thieu Le <thieule@chromium.org>
Reviewed-by: mukesh agrawal <quiche@chromium.org>
Commit-Ready: Thieu Le <thieule@chromium.org>
diff --git a/metrics.cc b/metrics.cc
index 61b75cf..85e37cd 100644
--- a/metrics.cc
+++ b/metrics.cc
@@ -19,10 +19,19 @@
namespace shill {
// static
+// Our disconnect enumeration values are 0 (System Disconnect) and
+// 1 (User Disconnect), see histograms.xml, but Chrome needs a minimum
+// enum value of 1 and the minimum number of buckets needs to be 3 (see
+// histogram.h). Instead of remapping System Disconnect to 1 and
+// User Disconnect to 2, we can just leave the enumerated values as-is
+// because Chrome implicitly creates a [0-1) bucket for us. Using Min=1,
+// Max=2 and NumBuckets=3 gives us the following three buckets:
+// [0-1), [1-2), [2-INT_MAX). We end up with an extra bucket [2-INT_MAX)
+// that we can safely ignore.
const char Metrics::kMetricDisconnect[] = "Network.Shill.%s.Disconnect";
-const int Metrics::kMetricDisconnectMax = 1;
-const int Metrics::kMetricDisconnectMin = 0;
-const int Metrics::kMetricDisconnectNumBuckets = 2;
+const int Metrics::kMetricDisconnectMax = 2;
+const int Metrics::kMetricDisconnectMin = 1;
+const int Metrics::kMetricDisconnectNumBuckets = 3;
const char Metrics::kMetricNetworkChannel[] = "Network.Shill.%s.Channel";
const int Metrics::kMetricNetworkChannelMax = Metrics::kWiFiChannelMax;